الرَّقِيبُ is translated as The Watchful One and The All-Observing.
It is that Being Who is protecting and always with us. He is observant of everything external and internal i.e. feelings, passing thoughts. We may pretend about something though we know what we are doing and why, but Allah ta’ala is watchful and observing.
Imam Ghazali (Rahimahullah) says, “For whoever cares for something to the point of never forgetting it, and observes it with a constant and persistent gaze — so that if one to whom it was forbidden knew about the surveillance he would not approach it: such a one is called observant. It is as though this name refers to knowledge and protection together, but with regard to its being constant and persistent, in addition to there being something forbidden and protected from access.
In the Qur’an
It is mentioned three times in the Qur’an.
مَا قُلْتُ لَهُمْ إِلَّا مَا أَمَرْتَنِي بِهِ أَنِ اعْبُدُوا اللَّهَ رَبِّي وَرَبَّكُمْ ۚ وَكُنْتُ عَلَيْهِمْ شَهِيدًا مَا دُمْتُ فِيهِمْ ۖ فَلَمَّا تَوَفَّيْتَنِي كُنْتَ أَنْتَ الرَّقِيبَ عَلَيْهِمْ ۚ وَأَنْتَ عَلَىٰ كُلِّ شَيْءٍ شَهِيدٌ
I never said anything other than what You commanded me to say, that is to worship Allah, Who is my Rabb and your Rabb. I was a witness over them as long as I remained among them; but when You called me off, You were the Watcher over them and You are a Witness to everything [Surah Maa’idah:117]
This is the episode of ‘Isaa AS when Allah ta’ala asked him if he had told the people to worship him (i.e. ‘Isaa AS) and ‘Isaa AS replied saying he had told them what Allah ta’ala had commanded him to say.
In Surah Ahqaaf, Allah ta’ala says He is watchful over everything.
We should know and feel that Allah ta’ala is الرَّقِيبُ and Scholars say the best way to do that is to make Dhikr and reflect (Muraaqabah).
A man came to the Prophet sallallaahu ‘alayhi wasallam and said, “Messenger of Allah, the laws of Islam have become too many for us, so [give us] a means of access to which we can cling which is comprehensive.” He, sallallaahu ‘alayhi wasallam said, “Let not your tongue cease to be moist with the remembrance of Allah.”
The feeling that Allah ta’ala is watching me should always be present. This is similar to being aware of security cameras being there in a shopping mall which prevents a person from doing anything wrong. So to know that Allah ta’ala is ever watchful.
Be watchful over your own heart and its intentions. Ask yourself why you did a certain act or said certain words and in this way be watchful over your Nafs and Shaytaan’s tricks. By being Raqeeb over our own hearts in this way we can work on our own selves in a productive way.
Imam Ghazali (Rahimahullah) says, the attribute of watchfulness is only praiseworthy in man if his watchfulness is directed to his Lord and his heart. And that will be the case when he knows that God the most high observes him and sees him in every situation, as well as knowing that his own soul is an enemy to him, and that Satan is his enemy; and that both of them take the opportunity to prompt him to forgetfulness and disobedience. So he becomes wary with regard to both of them by noticing their abode, their deceptions, and the occasions of their eruption, so that he can block both of them from using the entrances and the exits to his heart — that is his watchfulness.